A number of species have been introduced either deliberately or accidentally. Many of these come from countries with a climate similar to that of Gibraltar e.g. South Africa and parts of South and Central America. These have no trouble in settling in and spreading, sometimes to the detriment of native species. Among these plants are Oxalis pes-caprae (Bermuda Buttercup); Agave americana (Century Plant); Carpobrotus edulis (Hottentot Fig) which was introduced in order to stabilise the great eastern sand slopes; Opuntia ficus-indica (Barbary Fig); Freesia refracta (Freesia); Aloe arborescens (Tree Aloe).